1. Field of the Invention
The present invention relates to a bidirectional optical assembly, in particular, the invention relates to a bidirectional optical assembly having two ports for an optical transmitter.
2. Related Prior Art
A bidirectional optical assembly comprises an optical transmitting subassembly (hereinafter referred by TOSA) for a transmitting channel, an optical receiving subassembly (hereinafter referred by ROSA) for a receiving channel, an optical fiber and a housing. The housing forms a tubular shape, one end of which secures the TOSA that is arranged along an axis of the tube, while, the other end thereof secures the optical fiber to optically couple with the TOSA in precise. On the other hand, the ROSA is supported in the side of the tubular housing and coupled with the optical fiber via an optical filter. Refer to Japanese patent application published as JP-2003-524789A.
It is known that one type of the bidirectional optical assembly with two channels for the transmission includes two TOSAs and one ROSA independent to each other. In this assembly, each of the optical transmitting subassembly and the optical receiving subassembly couple with the respective optical fibers, and respective optical fibers are attached with an optical filter to transmit signal light with preset wavelengths. Moreover, the optical fibers are coupled with the optical coupler. This type of the optical assembly is hard to miniaturize and is relatively cost un-effective because the assembly requires a number of optical element, for instance, the optical filter and the optical coupler.
The present invention is to provide a bidirectional optical assembly having two transmitting channels with a miniaturized shape and a low-cost.